1. Field of the Invention
This invention relates to a speaker system for use in an acoustic apparatus.
2. Description of the Related Art
Most conventional speaker systems employ the construction wherein a speaker driver unit (hereinafter called the xe2x80x9cdriver unitxe2x80x9d) is fixed by screws to the front of a speaker box (hereinafter called the xe2x80x9cboxxe2x80x9d).
In this conventional construction, vibration of the driver unit is likely to be transmitted to the box. Therefore, the box generates noise that is out of phase, and this noise is one of the factors that disturb the sound. According to the conventional construction, a yoke side of the driver unit is kept floating and is likely to vibrate. Consequently, when a cone for generating sound moves in the driver unit, the yoke side vibrates due to its reaction. This lowers energy transmission efficiency from the cone to air and deteriorates the transient characteristics of the sound.
Proposals are disclosed to solve these problems in Japanese Unexamined Patent Publication (Kokai) Nos. 11-146471, 5-153680, etc, but these apparatuses are not structurally strong and invite breakage of the products due to vibration during transportation.
It is therefore an object of the present invention to provide a speaker system having a construction in which vibration of a cone of a speaker is not easily transmitted to a box, energy transmission efficiency from the cone to air is high, and the product is highly resistant to breakage due to vibration during transportation.
To accomplish this object, the present invention provides a speaker unit comprising a speaker stand (hereinafter called the xe2x80x9cstandxe2x80x9d), a driver unit directly fixed to the stand, a box comprising a front box and a rear box, for accommodating therein the driver unit. The front box and the rear box are fixed to the stand by clamping the stand through a buffer material, and the box is directly fixed to the stand. A cushion, a gel, a spacer having a high vibration absorption coefficient, a felt, and so forth, can be used for the buffer material.
According to the present invention, the box is fitted to the stand through the buffer material, and the box and the driver unit are not mechanically coupled with each other. Therefore, the vibration of the cone of the speaker is not easily transmitted to the box, and the sound does not become turbid. Because the speaker can be fixed to the stand at an earth position, it can efficiently output sound energy. Because the box is directly fitted to the stand, the mechanical strength can be improved, and breakage during transportation can be reduced.
The front box and the rear box can be fixed to the stand by using a screw. In this case, it is possible to employ a screw-fixing structure from the front surface side of the front box or a screw-fixing structure from the rear surface side of the rear box, or from both front and rear surface sides. The box can be integrated by fixing one of the front and rear boxes to the stand, forming a screw at an engagement portion of the front and rear boxes, and mutually screw-fixing both boxes.
When a screw insertion hole is formed in the front box side, this hole may be utilized to fit a protective bar in order to protect the driver unit and to cover the screw insertion hole. A protective net may cover the front box to protect the driver unit and to cover the screw insertion hole.
In the present invention, the front box and the rear box can be fixed to the stand by means other than screw fixing.
In this case, a screw is threaded at a mutual joint portion of the front and rear boxes and one of the boxes is fixed to the stand by using this screw through the buffer material. The other box is fixed to the box so fitted, by using the screw described above.
In another embodiment of the present invention, the front box and the rear box include means for integrally coupling them, and may further have a construction wherein the front box and the rear box clamp the speaker stand through the buffer material, when they are integrated, by using the coupling means.
In the present invention, as explained above, the driver unit is directly fixed to the stand and can therefore efficiently output sound energy. In contrast, a weight may be fitted to the rear surface of the driver unit so that the driver unit can be fixed to an immovable foundation. In this case, even when the cone moves, the vibration of the driver unit can be suppressed. In consequence, sound energy can be outputted efficiently. In this embodiment, a sound absorption material preferably covers the periphery of the weight. Furthermore, when the stand is disposed at the center of gravity of the driver unit and the weight, the balance of the speaker system can be improved with an improvement in the mechanical strength.
The speaker system according to the present invention can be applied to a bass-reflex speaker. In this case, a sound absorbing material for absorbing unnecessary resonance sound is preferably arranged around the bass-reflex port. When the sound absorbing material is disposed inside the box, unnecessary resonance sound can be absorbed and tone quality can be improved. Since the bass-reflex port is utilized to fit the sound absorbing material, the fitting structure of the sound absorbing material can be simplified.
Incidentally, means for fixing the sound absorbing material to the bass-reflex port according to the present invention can be applied to speakers having an ordinary construction. For example, the present invention can obtain a similar effect when applied to the conventional speaker having a construction wherein the driver unit is fitted to the box.